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Original poster
Apr 12, 2001
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42mm-SS-LB-Apple-Watch1-250x276.jpeg
One of the Apple Watch features Apple often highlights is the device's precise timekeeping, which Apple says is within 50 milliseconds of the global time standard. Apple's VP of Technology, Kevin Lynch, today spoke with Mashable and The Telegraph to share some details on how Apple achieves that level of accuracy.

Lynch told Mashable that the Apple Watch is so accurate that the hands of two Apple Watches placed next to one another will move in perfect unison. This is achieved primarily through 15 Network Time Protocol (NTP) servers that Apple has around the world, kept inside of buildings with GPS antennas that connect to GPS satellites broadcasting time data from the U.S. Naval Observatory in Washington, D.C. The Observatory houses an ultra accurate atomic clock, which uses electronic transition frequency to measure time.

Apple's time servers communicate the time to iPhones across the world, and the iPhone in turn syncs with the Apple Watch via Bluetooth to provide the exact time. Communicating a GPS signal from a server to an iPhone to an Apple Watch over Bluetooth has its own delays, which Apple corrects for via software. Apple's NTP servers make sure iPhones and Apple Watches keep time at "Stratum One" accuracy, within milliseconds of "Stratum Zero" devices.

Speaking to The Telegraph, Lynch also described the hardware inside of the Apple Watch that makes sure the time remains accurate. Each Apple Watch has a temperature-controlled crystal oscillator inside to combat time drift that clocks and watches see. The oscillator also makes sure the Apple Watch remains warm enough to keep accurate time in very cold climates. Thanks to this hardware, the Apple Watch is even more accurate than the iPhone.
"The second hand on every Apple Watch is perfectly in sync, and each device is accurate to 50 milliseconds of Co-ordinated Universal Time (UTC), the world's time standard, which is below human perception, so when you look at it you can't tell the difference," he explains.
With New Year's Eve approaching, Lynch says Apple Watch owners will have the most accurate watches in the room. "If you're in a room on New Year's Eve wearing one, you will be the best reference for when the New Year actually begins," he said.

Article Link: Apple's Kevin Lynch Explains Method Behind Apple Watch's Precise Timekeeping
 

captain cadet

macrumors 6502
Sep 2, 2012
417
648
Am I the only one that doesn't care about time accuracy that much? My non smart watch is about 1 minute out and I dont see why I need to change it - yes it be on time but 1 minute either side isn't going to make a difference - you dont tell people the time is exactly 3.03pm but you say 3.05 or 3.00 or just past...
 

Tech198

Cancelled
Mar 21, 2011
15,915
2,151
Talk about accuracy..

so every Apple watch owner will count the milliseconds up to New Years eve, then they'll make a big deal about "Hey, it really is that accurate." ?

Too bad we can't say the same reason for why we're late to the office.

Another way to think of this would be "Wear an Apple watch and never be late for anything again."
 

johnnyjibbs

macrumors 68030
Sep 18, 2003
2,964
122
London, UK
It's good to know that the Apple Watch actually keeps time. I love mine and I love that it keeps time. It's that important.

It's a pity that digital TV and radio are always broadcast a few seconds behind these days but on the analogue in the car I actually do find it hard not to look up at my Apple Watch's second hand as it moves round to zero precisely in time with the famous 'pips' (that bring in each hour) on BBC Radio 4 :p
 

captain cadet

macrumors 6502
Sep 2, 2012
417
648
Also are people interested precicly when the new year starts? My iPhone said we started singing Auld Lang Sine 30 seconds early last year (from video metadata) but did anyone really care? Not really as the fireworks had started and everyone around us thought it had started
 

macduke

macrumors G5
Jun 27, 2007
13,140
19,677
I've seen my wife's iPhone 5 and my old iPhone 6 Plus be as much as a couple minutes off. Haven't checked with my 6s. I checked her settings and it wasn't manually configured or anything—so they should be pulling from the same time server. We should be in sync. I've also noticed small differences with my iPads in the past. So either a software update fixed that or they really aren't that perfect.
 

yticolev

macrumors 6502
Sep 27, 2015
298
274
Correct me if I'm wrong, but I think it is incorrect to say that Apple has 15 NTP servers. Those are military NTP servers and Apple is merely reading the time on GPS signals that are originated by the military NTP servers. Unless Apple is now in charge of the military's GPS system and satellites and controls what is being transmitted.
 

johnnyjibbs

macrumors 68030
Sep 18, 2003
2,964
122
London, UK
Am I the only one that doesn't care about time accuracy that much? My non smart watch is about 1 minute out and I dont see why I need to change it - yes it be on time but 1 minute either side isn't going to make a difference - you dont tell people the time is exactly 3.03pm but you say 3.05 or 3.00 or just past...
Yes, but not having to keep "fixing" the time on your watch is an advantage. It's surprising how many of my clocks around the house need adjusting every couple of weeks (I've never had a microwave that keeps decent time!)
 

DocMultimedia

macrumors 68000
Sep 8, 2012
1,586
3,714
Charlottesville, VA
Kevin Lynch was a really bad hire for Apple. Over many years at different companies bad things always happen with the product he was working on. They tend to dry up and go away. How many use ColdFusion on their web servers? How many remember how he killed most every product when Macromedia brought him on? And then Adobe. Ugh. I truly fear for the Apple Watch just because of him. I'll of course buy v2 and try to forget he is in charge.
 

captain cadet

macrumors 6502
Sep 2, 2012
417
648
Yes, but not having to keep "fixing" the time on your watch is an advantage. It's surprising how many of my clocks around the house need adjusting every couple of weeks (I've never had a microwave that keeps decent time!)
Its just that time as I haven't been bothered to change it - its been like that since I had it 2 years ago (Its digital and the way I change time zones doesn't affect seconds)

And I dont think many people buy microwaves as they can keep their time within .01 accuracy...
 

uptempos

macrumors member
Jan 25, 2015
81
55
""If you're in a room on New Year's Eve wearing one, you will be the best reference for when the New Year actually begins,"

I guess he's never heard of atomic timekeeping thats been around on g shocks for the last ten years, and g-shocks have GPS waveceptors that has also been around..
 

kdarling

macrumors P6
One of the Apple Watch features Apple often highlights is the device's precise timekeeping, which Apple says is within 50 milliseconds of the global time standard.
Apple's NTP servers make sure iPhones and Apple Watches keep time at "Stratum One" accuracy, within milliseconds of "Stratum Zero" devices.

50ms is not Stratum One accuracy, not by a factor of several ten thousands (over four orders of magnitude).

Lynch told Mashable that the Apple Watch is so accurate that the hands of two Apple Watches placed next to one another will move in perfect unison.

Cute, but that would likely be true of any set of clocks in the same room, because they're all likely using the same network path out of that room, to the same NTP server.

It'd be much more meaningful if they said, "two Apple watches on opposite sides of the globe talking to two different NTP servers, one from an African cell site, and one over WiFi in NYC, would move in perfect unison."
 

oneMadRssn

macrumors 603
Sep 8, 2011
5,978
13,990
I need my watch to (a) correct for relativistic effects of my movement, and (b) take into account the time it takes for the light to travel from the watch face to my eyes, adjust automatically based on the distance between the two, and the time it takes the signal to travel from my eyes to my brain. Time must not be just precise, it needs to be precise as to exactly when I perceive it. Also make it thinner.
 
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